The world has two kinds of measles problems.

In low-income countries like Madagascar and in strife-ridden countries like Yemen, the disease takes a toll because vaccines are not available or accessible or affordable. In Madagascar alone, there have been nearly 80,000 cases and an estimated 900 deaths since September.

A Norwalk teen who got vaccinated against his mother's wishes testified Tuesday before a U.S. Senate committee examining preventable disease outbreaks.  

There's strong new evidence that a common childhood vaccine is safe.

A large study released Monday finds no evidence that the vaccine that protects against measles, mumps and rubella increases the risk of autism. The study of children born in Denmark is one of the largest ever of the MMR vaccine.

All U.S. states require most parents to vaccinate their children against some preventable diseases, including measles, mumps, rubella and whooping cough, to be able to attend school. Such laws often apply to children in private schools and day care facilities as well as public schools.

Editor's note: This story was originally published in 2015 and has been updated.

In 1962, children's book author Roald Dahl lost his oldest daughter, Olivia, to measles. She was 7 years old.

Twenty-six years later, Dahl wrote a letter to parents about what happened:

Health officials in Washington have declared a state of emergency and are urging immunization as they scramble to contain a measles outbreak in two counties, while the number of cases of the potentially deadly virus continues to climb in a region with lower-than-normal vaccination rates.

If you take the long view, international health organizations have much to be encouraged about when it comes to the global fight against measles. From 2000 to 2017, for instance, the annual number of measles-related deaths dropped 80 percent — from a toll of over half a million to just under 110,000 last year.

The Centers for Disease Control says more Ohio kids are getting the measles, mumps and rubella vaccine on time.

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The U.S. Surgeon General is urging central Ohio parents to vaccinate their kids. 

Ohio is tied with Colorado and West Virginia for the lowest measles vaccination rate in the country. 

With the recent breakout of measles and mumps, medical groups in Ohio are ramping up efforts to encourage immunizations.

Health officials say the central Ohio mumps outbreak that resulted in nearly 500 cases of the contagious viral illness has ended.

Measles Outbreak Over?

Sep 9, 2014

State health officials say the measles outbreak that helped push the number of cases to a two-decade high appears to have ended.

No New Measles Cases Since Mid July

Aug 16, 2014

Local and state health officials say no measles cases have been reported since mid-July, while mumps cases continue to be tallied.

Ohio's measles outbreak appears to be coming to an end. 

The Mumps and measles outbreaks continue to expand through central Ohio.

Geoff Caddick / AFP/Getty Images

About 80 more measles cases have been confirmed over the past week, bringing the total for an Ohio outbreak to about 240 cases across six counties. 

The Centers for Disease Control says measles cases are at a 20-year high, and 60-percent of those cases are in Ohio.

Number Of Confirmed Measles Cases Doubles

May 23, 2014

Ohio Department of Health officials have confirmed 143 cases of measles in six counties, with the number of confirmed cases doubling in the past two weeks.

Ohio health officials have distributed nearly 12-thousand doses of vaccines to try to stem recent outbreaks of measles and mumps in the state. 

Health officials have now confirmed 328 cases of mumps in the outbreak that started at Ohio State University.

Health officials tracking measles and mumps outbreaks in Ohio are urging residents to stay up-to-date on immunizations to prevent illnesses from spreading.  

The Ohio Department of Health has now confirmed 21 cases of measles in an outbreak that began in Knox County among unvaccinated Amish who had traveled to the Philippines, which has a measles epidemic.

Sixteen cases of measles have been confirmed among Amish in the Knox County area of north-central Ohio.

Knox County Health officials are working with the Centers for Disease Control to confirm 13 suspected cases of measles.